Development Of Acetylcholinesterase Biosensor And Its Application In Pesticide Residues Detection

In this paper, acetylcholinesterase (AChE) biosensor was constructed todetect pesticide residues. On the basis of the original laboratory, we furtherstudied the impact of the different modified materials and modification methodson the performance of AChE biosensor based on the traditional electrode. We alsostudied the feasibility of the AChE biosensor based on interdigitated arraymicroelectrodes (IAMs) in the determination of pesticides. The specific work wasas follows:1. Studies on AChE biosensor based on poly(diallyldimethylammoniumchloride)/gold nanoparticles/multi-walled carbon nanotubes modified electrode.When multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs)were used as carrier materials to modify electrode, they could improve the microenvironment and electrochemical response of the electrode. Poly(diallyldimethy-lammonium chloride)(PDDA) was bound electrostatically to AChE bylayer-by-layer assembly technique, which could increase AChE loading amountand improve the stability of the biosensor. The AChE biosensor showed goodperformance for pesticides determination such as short respose time, and goodstability. In this study, the linear ranges between inhibitions of pesticides andconcentrations were0.8to20ng/mL and20to300ng/mL, the detection limit was0.56ng/mL (S/N=3).2. Studies on AChE biosensor based on poly(diallyldimethylammoniumchloride)-multi-walled carbon nanotubes-graphene hybrid film modified electrode.In order to explore a simpler, quicker and better method, here we introducedgraphene. It was combined with other materials to made hybrid, which couldmodify electrode by one step dipping method. The solubility of MWCNTs and GRwas greatly improved by preparing PDDA-MWCNTs-GR composite. Comparedwith the first method, the proposed biosensor had better property. And theoperation was simpler, and much easier to master.3. Studies on AChE biosensor based on interdigitated array microelectrodes.IAMs have many advantages, they are easier to realize miniaturization of equipment and testing online. However, biosensors based on IAMs were mainlyused to detect virus and bacteria. There was nearly no report about AChEbiosensor based on IAMs used to detect pesticide residues. In this study, thebiosensor was fabricated using CHIT to immobilize AChE, and combined withelectrochemical impedance spectroscopy (EIS) to detect pesticide residues. Theproposed biosensor can be used in the determination of pesticide residues.